Range Rover P38
LAND ROVER V8
41
DESCRIPTION AND OPERATION
If the crankshaft sensor fails, the engine will stop and
fail to restart. There is no back-up strategy or limp
home facility programmed into the ECM. If a fault
occurs whilst the engine is running, the engine will
stall and a fault code will be stored in ECM memory. If
the fault develops while the engine is not running, the
engine may not be capable of starting and no fault
code will be available. In this case, the MIL light will
still be illuminated.
In the event of a CKP sensor signal failure, the
following symptoms may be observed:
•
Engine cranks but fails to start
•
MIL remains on at all times
•
Engine misfires (CKP incorrectly fitted)
•
Engine runs roughly or stalls (CKP incorrectly
fitted)
•
Tachometer fails to work
•
Flywheel adaption reset -- ferrous contamination
Possible causes of CKP sensor failure include the
following:
•
CKP sensor not fitted correctly (or assembly
loose)
•
Incorrect length spacers fitted
•
Sensor/wiring open or short circuit
•
Sensor bent or damaged by reluctor ring
•
Water ingress at sensor connector
•
ECM unable to detect the software reference
point.
•
Ferrous contamination of crank sensor
pin/reluctor.
Whenever a new CKP sensor is fitted or the flywheel
is removed, the adaptive values have to be reset
using Testbook.
Should a malfunction of the component occur, the
following fault codes may be evident and can be
retrieved by Testbook:
•
P0335 - (reference mark is outside search
window with engine speed above 500 rev/min for
more than 2 revolutions.
•
P0336 - (incorrect number of teeth detected
±
1
tooth between reference marks with engine
speed above 500 rev/min.
In addition to crankshaft position, the ECM also uses
the CKP sensor signal to determine engine speed.
The ECM shares the engine speed information with
the electronic automatic transmission (EAT) ECU by
transmitting the data via the CAN link. Engine speed
output is also provided to the instrument pack
(tachometer), for which the output signal is scaled
down to 4 pulses per crankshaft revolution.
The ECM also has a quick start facility, where the
position of the crankshaft and camshaft are
memorised when the engine is stopped. This stored
information is used to facilitate immediate sequential
fuelling during cranking.